In 2006 King won her only WTA singles title at the PTT Bangkok Open, a Tier III tournament. She defeated Tamarine Tanasugarn in the final. On November 6, 2006, King achieved her career-high singles ranking of world no. 50.

King then traveled to the Monterrey Open. In doubles, she reunited with Groenefeld and reached the finals as the top seed, falling to second-seeded Benešová/Záhlavová. In singles, she lost in the quarterfinals to second seed Daniela Hantuchová.

King's next Premier was the Family Circle Cup in Charleston, where she reunited with Krajicek and reached the final, before falling to top seeds Liezel Huber and Petrova. In singles, she lost to Petrova in the second round.

King then entered the Strasbourg International. In the doubles tournament, she partnered with Alizé Cornet and won the tournament after an injury to Lucie Hradecká forced top seeds Hradecká/Chuang to retire in the second round. King/Cornet defeated second seeds Rodionova/Kudryavtseva in the final for her 10th tour doubles title. In singles, King defeated second seed Elena Vesnina in the first round and reached the semifinals, before falling to Kristina Barrois.

King made it to the finals of five other WTA tournaments in the course of the year, one in Monterrey with Anna-Lena Grönefeld and in Rome, Cincinnati, Osaka, and Moscow with Shvedova. She and Shvedova won the events in Cincinnati in August and Moscow in October.

In singles action in 2013, King lost in the Guangzhou final to Shuai Zhang. King lost in the second round of the French Open and in the first round of the other three Slans. In doubles that year, her best finish was a finals loss in Guangzhou.

Partnering Jie Zheng of China, she made a quarterfinal appearance in Madrid, losing to Sara Errani and Roberta Vinci. Then followed a series of first-round losses, including Roland Garros and Wimbledon.

She had some success in the late summer, making the quarterfinals in Washington, D.C. partnering Taylor Townsend and the third round at the US Open partnering Lisa Raymond.

In singles, she made the semifinals in Shenzhen, but had to concede a walkover. She made a first-round exit at the Australian Open at the hands of Carla Suárez Navarro. At the Pattaya Open, she was defeated by Elena Vesnina in the first round. A series of first-round defeats followed in Rio de Janeiro, Florianópolis, and Indian Wells.

She made the second round in Miami and Charleston, but it was not until April in Bogotá that she found some form and made it to the semifinals. She went down in the first round in both Roland Garros and Wimbledon, but she did make the quarterfinals in Washington, D.C..

King missed the first three Slams of 2015 due to injury. She lost in the first round of singles and the second round of doubles there in Flushing. The highlight of her year came on hard courts in Waco, where King and Nicole Gibbs won in November, defeating Julia Glushko and Rebecca Peterson 6-4, 6-4.

At the Australian Open, King and Shvedova advanced to the third round, where they lost to Mirjana Lucic-Baroni and Andrea Petkovic. They were stopped in the second round of Indian Wells by the Japanese-Chinese pair of Shuko Aoyama and Zhaoxuan Yang. In Miami, they went on to the quarterfinals, where they again lost to Mirza and Strycova.